Question

20 ℃ Liquid water is flowing into a chamber with a mass flow rate of 1.5 kg/s and heated by mixing it with a superheated steam at 300 ℃. For a specified mixing temperature at 60 ℃, what is the mass flow rate of the steam we need to set and what is the mass flow rate of the 60 ℃ water we can get? Assume: • Mass flow rate ?̇ is the mass change per unit time, with the unit of kg/s; • This is a steady-flow process since there is no change with time. • Kinetic and potential energy changes are negligible. • There are no work interactions. • The mixing chamber is steadily releasing heat to the surrounding with the rate of 600 KJ/min • The mixing chamber is constantly maintaining an internal pressure of 200 kPa • Specific enthalpy h of liquid water at 20℃ is 83.96 KJ/kg, at 60 ℃ is 251.13 KJ/kg, at 300 ℃ is 3071.8 KJ/kg

Answer 1

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